1. Field of the Invention
The present invention relates to an improved data processing system and, in particular, to a method and apparatus for multicomputer data transferring. Still more particularly, the present invention provides a method and apparatus for computer-to-computer authorization.
2. Description of Related Art
There are two broad categories of approaches to providing commercial services for categorizing and locating information on the Web: (1) search engines that return direct hits to sites containing data that match inputted queries, such as AltaVista; (2) Web portals that organize the information into categories and directories, such as Yahoo!. These systems operate using a traditional client-server model for requesting and receiving search results.
The amount of Internet content continues to grow rapidly and to outpace the ability of search engines to index the exploding amount of information. The largest search engines cannot keep up with the growth, and it has been estimated that search engines only index about 5% to 30% of the information content on the Web. Hence, at the current time, the majority of Web content is not classified or indexed by any search engine.
Since the Web is a dynamic environment where content is constantly being added, updated, and changed, it is very difficult for centralized search engines to be up-to-date. The traditional Web client-server paradigm has been challenged by distributed file-sharing systems that support a peer-to-peer model for exchanging data. In peer-to-peer networks, each computer platform, or node, can operate as a hub, i.e., each node has both client functionality and server functionality. Each node has a list of addresses, most commonly Internet Protocol (IP) addresses, of several other nodes, or “peer nodes”. These nodes can directly communicate with each other without a central or intermediate server.
Nodes within a peer-to-peer network form a distributed file-sharing system in which the nodes act cooperatively to form a distributed search engine. When a user at a node enters a search query, the search query is copied and sent to its list of peer nodes. Each peer node searches its own databases in an attempt to satisfy the search query. Each node copies the query to each node in its list of peer nodes while observing a time-to-live value in the query message. If a resulting query hit is made, then the node returns some type of query results to the originating node. A peer-to-peer search quickly fans out amongst a large number of nodes, which provides a useful manner for finding new content that has not yet been indexed by the large search engines.
Although peer-to-peer networks provide some advantages for finding content, each node within a peer-to-peer network is typically limited in terms of its available resources and its reach to other peer nodes. Hence, some of the advantages of both centralized indexing and peer-to-peer networks have been combined to produce so-called hybrid peer-to-peer networks. In these networks, a centralized server performs the majority of the indexing duties by indexing files that are available at the peer nodes while the peer nodes continue to store the files that have been indexed. In a hybrid peer-to-peer network, a user of a peer node locates a desired file through the centralized index and then retrieves the desired file from an identified peer node.
In comparison to the index that is created by a typical Web search engine, which constructs an index from content within files, the index at a centralized indexing server in a peer-to-peer network is somewhat limited because its index is generally constructed from a small amount of metadata about each indexed file, such as file size, title, author, date of publication, or other bibliographic data. Hybrid peer-to-peer networks work especially well, though, for certain types of files in which the content cannot be indexed and for which bibliographic data is sufficient for finding files of interest. For example, commercial services based on a hybrid peer-to-peer network are becoming available for purchasing and downloading audio and video files, which are selected through the use of bibliographic metadata.
While peer-to-peer networks have typically been created on an ad-hoc basis, enterprises are discovering commercial and non-commercial applications for peer-to-peer networks. In many situations, an enterprise does not want to create a massive centralized archive of all files that are created by employees of the enterprise, yet it would be convenient if employees of an enterprise could locate files of interest throughout the enterprise. Since most enterprises maintain some form of centralized data processing servers, hybrid peer-to-peer networks also work well within an enterprise, which can maintain a centralized indexing server that regards the desktop computers within the enterprise as peer nodes in a peer-to-peer network.
Enterprises have authentication and authorization systems for maintaining the integrity of data processing systems and the information that is stored within them. In a similar manner, commercial enterprises try to restrict access to their services to paying customers. While it may be convenient for users to have access to a hybrid peer-to-peer network for a commercial service or within an enterprise, the need for restricting file access to authorized users remains an issue for hybrid peer-to-peer networks. Therefore, it would be advantageous to provide a method and system for distributed access control within a peer-to-peer network.